I just rescued an 820 projector that I need for a short use. It seems to run smoothly, lamp looks fine, audio is not needed.

I'm going to run it to view several 400' reels. I have no idea of it's history and I would think it would need some lubrication somewhere. The old manual I found online mentions the felt pad near the shutter needing lube but I'm not sure what modern replacement would be appropriate.

Likely a light weight oil such as clock oil or possibly gun oil. Movie theater projectors used an oil similar in viscosity to mineral oil.
If the felt pad is for the shutter movement then the the temperature characteristics of the oil are important.

I have some light lubricant I used on a model flying helicopter that also contains PTFE. In this case itís for a felt pad that puts pressure on the shutter and itís very close to the bulb, Iíll check itís temperature range. Otherwise Iíll order your suggestion. Many thanks!